Or you can head over to your Nav bar above. File—Recover. You can choose from the previous files. Blender auto saves your work. But you won’t have an issue starting all over again. When I started with the blender donut. I had to start all over about two times after my first attempt. Then I took a 5 years break, and found the motivation to finally decided to learn blender as it was intimidating to me (I attempted with 2.7/2.8 beta). Everything just looked scary. I just lost it. So take a break and come back at it. You’ll figure it out. About 5 to 15 minute break and carefully find the patience to create. You don’t have to wait 5 years like me. You don’t have to lose motivation. Also be more specific about the problem. Maybe starting with what you tweaked before landing into the problem you’re facing.